There is a growing group of HIV-seropositive patients at risk for chronic lung disease due to their life style and age. The interaction between certain antiretroviral drugs and corticosteroid inhalation therapy is potentially dangerous but often unrecognised. We present three cases from our HIV-clinic of whom two developed full blown Cushing's syndrome over a short period of time and one presented with asymptomatic hypocortisolaemia due to serious drug interactions between HIV-drugs and inhaled corticosteroids. General practitioners, HIV and chest physicians should all be aware of this potentially life-threatening interaction and the combination of those products should be avoided where possible.